1. Field of the Invention
The invention relates to a packaging device for a fluid product. The invention can be particularly advantageous for a liquid or viscous product such as may be found in the fields of cosmetics, paints or adhesives. More particularly, the invention can be advantageous in the field of cosmetics, with the product, for example, a nail varnish or nail polish composition or other nail care product.
2. Discussion of Background
Generally, a nail varnish or polish applicator set includes a reservoir for the product to be applied and a product applicator, such as a brush with a tuft of bristles attached to a first extremity of a rod. The rod is fixed at its other extremity in a cap intended to close the reservoir so that the tuft of bristles is immersed in the product when the applicator set is closed.
To ensure efficient closure of the unit, the reservoir includes a neck incorporating a first screw thread which engages with a second screw thread provided in the cap. The cap includes a transverse wall which is in contact with the upper edge of the neck when the applicator set is closed. The screw thread is formed over the full height of the neck and is flush with the upper extremity of the neck.
In this type of packaging, the neck opening is sufficiently large such that when the reservoir is in the open position the product is able to flow out of the reservoir if the reservoir is overturned.
Furthermore, to apply the product to the nail, the applicator impregnated with product is withdrawn from the reservoir. Generally, the brush carries an excess amount of product. It is therefore necessary to remove this excess product, and in order to do this the user strips the brush by wiping it on the end of the reservoir neck. The product may then remain on the neck and run along the external wall of the neck, thereby fouling the screw thread on the neck. When the cap is screwed back on to close the reservoir, the product is then spread over the neck and into the screw thread. The product then dries, thus forming a build-up on the cap/neck assembly. During subsequent use it becomes difficult, or even impossible, to unscrew the cap from the reservoir. Moreover, the product present on the neck prevents effective sealing of the applicator unit because the cap is no longer in leaktight contact with the upper edge of the neck.
To avoid having to wipe the brush on the rim of the neck, it is possible for example to use a stripper element mounted inside the neck as described in document GB 683,932. In this document, the stripper element is composed of a tubular element terminating in a tapered portion which converges towards flexible lips. The flexible lips define an opening having a diameter less than or equal to that of the stem of the brush. When the cap is opened, the brush is stripped by the stripping lips and the user no longer needs to wipe the brush on the rim of the neck. In this device, the stripper element includes a flange which bears against the upper extremity of the neck. This is also the case with the stripper element described in U.S. Pat. No. 5,284,239.
U.S. Pat. No. 5,961,238 also describes a stripper element mounted inside the neck of a reservoir. The stripper element incorporates a flange bearing not on the upper extremity of the neck but in an indentation provided inside the neck. However, the flange of the stripper element projects slightly beyond the upper extremity of the neck.
In the devices described in these two documents, the cap bears in a leaktight manner on the flange of the stripper element. When the brush is withdrawn from the reservoir, product can be deposited around the neck opening, and therefore onto the flange of the stripper element, so that when the cap is reclosed the product can cause the stripper element to stick to the cap as it dries. At the next opening, the stripper element can tend to remain stuck to the cap and to come out of the neck or at least be displaced inside the latter.